Stabilized diazo printing paste



Patented Aug. 22,1944

STABILIZED DIAZO PRINTING PASTE' Swanie S. Rossande'r, Chiles E. Sparks,and Carl W. Maynard, Jr., Wilmington, Del., assignors to E. I. du Pontde Nemours & Company, Wilmington, Del., a. corporation of Delaware NoDrawing. Application May 28, 1941 Serial No. 394,852

Claims.

The dyeing of textiles is frequently carried out by impregnating thetextile throughout with the coupling component of an azo dyestufl andoverprinting with a paste containing a diazo salt. By reaction of thediazo salt with the coupling component a colored pattern is produced onthe textile. The diazo salts incorporated in the printing paste are ofvarious'types, such as diazonium halides, reaction products of diazoniumhalides with zinc chloride or other metallic halides, and reactionproducts of diazonium halides with aryl sulfonic acids. Whenincorporated in the printing paste, certain diazo salts deterioraterapidly, their deterioration being particularly marked by loss instrength of colors made therefrom. Even so short a period of standing asone day has frequently produced so great; a change that the paste was nolonger useful for its intended purposes.

. The object of the invention, which has been accomplished by theinvention set forth in this patent, was to produce printing pastes whichdo not deteriorate so swiftly and keep their strength longer. Theprinting pastes of our invention contain, in addition to the diazo saltand the pasteforming ingredients, an aryl carboxylic acid, or a solublemetallic salt thereof, such as an alkali metal salt thereof. These acidsmay be substituted in the aryl nucleus by one or more negative groupssuch as nitro, halogen, trifiuoromethyl, and acyl. Other objects of theinvention and their method of accomplishment will be in part obvious andimpart set forth hereinafter.

The aryl carboxylic acids and their soluble metallic salts ,which form aconstituent of our new printing paste may be mixed'with any in-,

gredient of the paste prior 'toincorporation, or

may be mixed with the finished paste. If they are mixed with the diazocomponent, they can be incorporated therewith prior to or'afterdiazotization.

Exemplary of the aryl carboxylic acids which have been found useful inthis invention are terephthalic acid, 4-chloro-benzoic acid, phthalic'acid, 2-chloro-benzoic acid, 3-nitro-benzoic acid,

nitro-tereplithalic acid, 2,6-dichloro-benzoic acid,2-chloro-4-nitro-benzoic acid, 3-nitro-4-chlorobenzoic acid, dipl enicacid, 6-chloro-2-nitrobenzoic acid, trimesic acid,tetra-chloro-orthobenzoyl-benzoic acid, 2 -chloro-5-nitro-benzoic acid,3-trifluoro-methyl-benzoicacid, 3,6-dichloro-Z-benzoyl-benzoic acid,3-nitro-phthalic acid', 5-nitro-salicy1ic acid, phenyl-acetic acid,4-nitro-phenoxy-acetic acid, pyromellitic acid, and 2,5-dichloro-benzoicacid.

It has also been determined that the anhydrides of certain of theseacids, such as phthalic anhydride, can be effectively used asstabilizers.

' lene, anthracene, stilbene, and diphenyl series.

The following examples illustrate the invention.

In these examples parts are by weight and proportions are illustrativeof good practice and not limitations:

Example I I The complex diazo salt from diazotized 2,5- dichloro-anilineand zinc chloride was isolated in the usual manner,dried, and dilutedtoabout strength on an amine basis with benzoic acid and inactivediluents such as sodium sulfate in such a manner that the finished drysalt preparation contained 10% benzoic acid. A

printing paste of the following composition was prepared:

Grams Diazo sa 4 Water I 30 Starch-gum tragacanth thickener 66 When thisprinting paste was printed from an engraved roller on cotton fibrepreviously treated with the anilide of 2,3-hydroxy-naphthoic acid, astrong scarlet color resulted. Whenv the same .prlnting paste wasused atsuccessive time intervals for-printing in the same manner, thepersistence instrength 01' the resulting colors was far superior tothepersistence instrength of those colors obtained from a parallelseries of printings bilized diazo salt maintained its strength andoriginal physical appearance for much longer p ri ds of time.

Example II Example I was repeated, using 3,5-dinitrobenzoic acid inplace of benzoic acid. Similar marked'increases in the stability of thediazo salt printing pastes as compared with pastes containing nostabilizer were noted.

2 assaeiasam le In I A diazo salt printing paste was prepared by thefollowing diazotization formula:

' 3,5-dinitro-benzoate (lzl)-.

Sodium acetate (50%). 4.7

100.0 The paste was printed: as in Example I, and

, was found to be much more stable over a period of several days thanwas a similarly prepared printing paste in which thesodium-3.5-dinitrobenzoate ingredient was omitted.

. 2 Similar experiments with the stable complex diazo salt fromdiazotized meta-chloro-aniline with zinc chloride were carried out, and,in addition to the above listed stabilizers, the following diazo saltscontaining the acids were used? 4- nitro-naphthalic acid.1-nitro-anthraquinone- G-carboxylic acid, 2-(3-nitro-benzoyl) -benzoicacid, and anthraquinone-dicarboxylic acid. The 30 similar use of a diazosalt preparedfrom .diazo-w tized. meta-chloro-aniline andnaphthalene-1,5- disulfonic acid also gave attractive results.

Additional experiments carried out in a-similar manner on the diazosalts prepared from the fol- 3'5 lowing bases also gave increases in therelative stability of the resultant printing pastes: 4-nitro-Z-amino-anisole, 3-nitro-4-amino-anisole,

- 4-chloro-2-amin6-toluene, dianisidine, 4-chloroing agent at any stageafter the first'isolation in the preparation of the .diazo salt.'or byadding the stabilizing agent 'to a printing paste prepared bydiazotization of the corresponding base. It is not necessary to use thefree carboxylic acids.

since the water soluble metallic salts such as the alkali metal salts ofthe acids are usually equally effective in their stabilizing action. andoften present more attractive solubility characteristics. The anhydridesof the acids are frequently useful for the purposes of this invention.

The manner of drying the diazo salt, andthe diluents used. in thefinishing of the disco salt. have no effect on the new printing pastes.pro- 15 vided,'of course. that the diaso salt so prepared is otherwisesatisfactory for printing purposes.

- Many diazo salts in common use do not keep their strength in printingpastes for. more than a few hours, while the samediazo salts, in manycases,

maintain their printing paste strength for several days when included inthe pastes of our invention. Ilhe invention is of particular value wherelarge amounts of printing pastes are made up at one time, and used overa comparatively acids were found to be effectual in maintaining 25 thestrength of the printing pastes in which the long period.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that we do not. limit ourselves to the specific embodimentsthereof except as defined in the appended claims.

. We claim: I

1 A printing paste comprising water, the reaction product of a diazoniumhalide with a metallic halide and a non-coupling member from the groupconsisting of aryl carboxylic acids, the soluble metallic salts thereof,and their anhydrides.. 1

2. The composition claimed in claim 1 in, which 2-nitro-aniline,3-nitro-4-amino-toluene, 5-nitro- 40 theediazo body is a salt of zincchloride.

Z-amino-toluene, 4-chloro-2-amino-anisole, and l-amino-anthraquinone.

The stabilization may be brought about. by the use of various amounts ofthe stabilizing acid in the finished dry diazo salt. We prefer to useamounts of the stabilizer between five and fifteen percent of thefinished dry diazo salt. The same result may be obtained by adding thestabilizing acid and the diazo salt separately to the printing pasteformula. or by incorporating the stabiliz- 5 3. The composition of claim1 in which the non-coupling member is benzoic acid.

acid.

' SWANIE S. ROBSANDER.

CHILEB E. SPARKS.- CARL W. MAYNARD. Jx.

